To the Editor The main claim of the authors of the secondary analysis of the BrighTNess randomized clinical trial1 is that “patients with stages II to III TNBC who are not eligible for breast-conserving therapy (BCT) at presentation have an approximately 50% likelihood of converting to BCT eligible with neoadjuvant systemic therapy (NST).”1 This resulted in an overall increase in BCT eligibility of 7% (from 76.5% to 83.5%). However, the actual BCT rate after NST in 599 patients with pre- NST and post-NST evaluations for BCT eligibility was 57%, which is about 20% less than initially planned, and in agreement with a meta-analysis of 12 311 patients.2 We understand that eligibility to BCT does not necessarily translate into receiving this type of treatment also in patients not treated with NST. However, a potential increase in mastectomy rates in patients eligible to BCT and receiving NST merits further reasoning. Only 66% of BCT-eligible patients enrolled in BrighTNess underwent BCT, either because of loss of BCT eligibility (20%) or because of receipt of mastectomy despite being BCT eligible after NST (80%). Furthermore, 35% of patients who were not deemed BCT eligible after NST had pathologic complete response at final pathology.1 We believe that 3 issues are relevant at this point: (1) whether undergoing mastectomy despite being BCT eligible needs to be considered an undesirable outcome; (2) whether the process of NST itself leads to a reduction in BCT rates in patients who are BCT candidates at tumor diagnosis; and (3) whether response to NST can be used to tailor surgical choices. In the most chemoresponsive subtypes of breast cancer (triple-negative and HER2-positive), NST is becoming a preferred approach because of the possibility of correcting prognosis with additional, postsurgical treatments in patients failing to achieve a pathologic complete remission.3,4 Not unexpectedly, and in line with other NST trials, BrighTNess enrolled mostly patients who were candidates to BCT before NST (76%). Consequently, in a context where the main clinical motivation to NST will become the chance to tailor systemic treatments,5 if tumor downstaging is paradoxically accompanied by actual surgical upsizing, the widespread adoption of this strategy could potentially increase the overall mastectomy rate. It is of paramount importance to clarify motivations for the reduced BCT rates observed in BrighTNess and other NST clinical trials and to provide guidance to multidisciplinary breast teams dealing with patients with operable breast cancer who are considered candidates to NST.